In order to completely evict dozens of flying squirrels from the insulated spaces of a cathedral ceiling, openings were made along the ridge and eves, and all of the insulation and years of accumulated squirrel stuff was removed. The temporary openings were closed and a new metal roof was installed. The plan at this time is to wait a few months to let the space dry out and then blow in new insulation from the normal openings at the ridge vent.

My question are:

What sort of vapor barrier can be installed through  the ridge vent opening to prevent moisture and air flow from passing through the loose fitting tongue and grove ceiling paneling?

Is blown in fiberglass insulation the only option for this situation, or is there a very low expansion foam product which could be injected into  these essentially closed spaces?